Furnace for burning finely-divided fuel



w w R Q A R A Q 2 v FURNACE FOR Ewwamtz Patented Dec. 10, 1929 PATET F I if" E VIBGINIUS Z. CARACRISTI, OF BRONXVILLE, NEW YORK, ASSIGNOR TO LOCOMOTIVE PULVERIZED FUEL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF DELA- WARE FURNACE FOR BURNING FINELY-DIVIDED FUEL Original application filed Kay 6, 1921, Serial N'o. 467,345. Divided and this application filed December 1,

1925. Serial No. 72,447.

This invention relates to the art of combustion and is especially useful in connectlon with the burning of' fuel in finely divided form such, for example, as pulverized coal, under stationary boilers.

This application is a dlVlSlOIl of my copending application No. 467,345 filed May 6,1921.

One of the primary ob ects of my lnvention is to secure more perfect combustion of the fuel, with high furnace efficiency.

Another object of the invention is to accomplish the foregoing with minimum detrlmental efi'ect on the refractories.

Still another object of the invention 15 to provide a novel manner of and apparatus for burning finely divided fuel under certain types of boilers.

Other objects and advantages will appear hereinafter.

The foregoing, together wlth such other objects and advantagesas may be mcldent to my invention, are realized by the apparatus illustrated in preferred form in the accompanying drawing. a

The figure represents a vertical sect on thru a boiler and boiler setting embodying my improvements. 1

Referring now to the drawing, the reference character A denotes the combustion chamber, the upper end 7 of which 1s open. The fuel is delivered into oppo: ite sides of this combustion chamber, preferably 1n a downward direction thru rows of burners 8, adapted to deliver the fuel thru the arch portions 9. Preferably but a portion of the air required for combustion is supplied thru the burners, the balance of the air being provided thru rows 10 of air inlets in the opposing upright walls 11-11. The fuel and flame streams descend downwardly into the opposite sides of the combustion chamber until their downward momentum is overcome, whereby they turn in inwardly and then upwardly, the two streams uniting, as it were, back to back, and forming a single rising stream. By the foregoing arrangement, the fuel which can be effectively burned in a combustion chamber of this size is divided into two general streams, one at each side of the combustion chamber, each general stream being in the first instance composed of a number of individual small streams rapidly uniting into the general stream.

The incoming fuel, i. e. descending legs of the fuel and flame stream are subjected to radiant heat from therefractories and to radiant heat from the ascending middle leg of the fuel and flame stream and thus ignition takes place promptly. Where the two general streams tend upwardly, back to back, they subject each other respectively each to the radiant heat of the other and finally to actual contact so that combustion is furthered in these regions.

*Air sufficient for ignition enters thru the burners. Additional air, particularly that which enters thru the upper rows of inlets, passes between the streams delivered by the burners-into the space between the Us, thus supplying the oxygen into each. The portion of the air admitted thru the upper rows of inlets also continues to move into and downwardly with the descending fuel and 'flame stream, this being true also with respect to the various rows of inlets, arranged at successive levels. Thus the outside or convex portions of the two general fuel streams are supplied with the needed oxygen.

Further air may be admitted thru the row of inlets 12 at each side of the combustion chamber immediately above the floor portions 13 of the extension chambers a of the combustion chamber A. Similar air inlets 14 admit air immediately above the floor portion 15. Such air serves to create a cooling zone above the floor portions 13 and 15 preventing the formation of slag thereon, and it also serves to supply needed oxygen to the convex sides of the fuel streams.

Additional air may also be admitted thru the inlets 16- 16 at the top of the ash pit 6, depending upon the rate of firing of the-fuel, as is the case also with various of the other inlets mentioned. The airadmitted thru the inlets 16 serves substantially the same function as the air admitted thru the inlets 12 and 14; That is to say it prevents the formation as to secure more perfect combustion with high efliciency, whileat the same time slag is prevented from forming and the upright wall,

' particularly the walls 1111 are protected from the intense heat by virtue of the entering air, which, in part, creates a borderin envelope on the convex side of the fue streams.

It will further be seen that ample provision is made for the expansion of the gases 1iberated and of the incombustible air.

Arranged immediately above the combus tion chamber is a boiler B, this boiler comprisin' the two mud drums 17-17, one at each slde of the throat of the combustion chamber, the main upper drum 18, centrally located above the combustion space and the two upper drums 19-19, each drum 17 being connected to the drum 18 by an inclined bank bf tubes 20 and each drum 17 being connected to the drum 19 by an almost vertically arranged bank' of tubes 21. The banks of tubes 20 and 21 are baflled to provide three passes. The boiler is enclosed by the chamber 0, the walls of which rise outwardly and upwardly from the combustion chamber and are spaced away from the boiler to provide the outermost passes'22-22. The fork breaching 23 carries off the waste gases of combustion to the stack 24:.

Combustion is completed at about the level 'cerned. The space between the banks of tubes 20 decreases upwardly, thus compensating for the contraction of the gases resulting from the cooling efl'ect of the tubes by virtue of their absorption of heat. The flames are not caused to enter in among the tubes and hence the loss of combustibles is negligible. The second pass decreases. in .width thus compensating'for the further contraction of the gases passing over the baffles 20*. i

It will be noted that the ash pit, combustion chamber, boiler and boiler housing, breaching and stack, are one above the other.

In combination, a combustion chamber having a central draft outlet in the upper part thereof, means for admitting finely divided fuel into the chamber in a vertically downward direction at opposite sides of the draft outlet so that each fuel and flame stream under the influence of the draft describes a U-Shaped course from the point of admission portion of the to the outlet with the ascending legs thereof merging.

In testimony whereof I have hereunto signed my name.

VIRGINIUS Z. CARACRISTI. 

